With the popularity of the sport of cycling, there are more and more people riding bicycles for recreation. In a conventional bicycle brake system, the braking operation is driven by a rider who presses brake levers installed on handles, and the front and rear wheels will be braked accordingly. The conventional bicycle brake system performs the braking operation for each individual brake of front wheel and rear wheel. In other words, when only one of the levers is being pressed, it drives only the brake connected to that lever. The brake levers in related to a front wheel or a rear wheel are arbitrarily installed on left side handle and right side handle depending on every different manufacturer, so therefore when a rider with less physical reaction in choosing which wheel should be braked may cause an emergency incident, because of his/her wrong choosing of brake lever.
Accordingly, a rider pressing a wrong brake lever during a high speed riding may causes a flip over of a bicycle. Because if, in a high speed riding, a front wheel is suddenly braked prior to a rear wheel, the inertia force from the rear wheel will overwhelm the braking force in the front wheel to thus cause a flip over.
In addition, since a gravity center of bicycle is allocated on a frame body, the balancing itself is complicated. An emergency situation will let it even more complicated, since a rider becomes difficult to make a prompt analysis in such a rush moment to determine whether a front wheel, a rear wheel or both wheels should be braked. Moreover, to remember which brake lever corresponds to which wheel is another problem that a ride may not be able to react. Moreover, if a rider only brakes the rear wheel, it may cause the non-braked front wheel driving the bicycle to run a unexpected distance, which may also cause an accident.